Data services are generally grouped into two categories: circuit-oriented (which includes Asynchronous Data and Group-3 Fax services) and packet. For calls that support packet data services, a Packet Data Serving Node (PDSN) serves as an interface between the transmission of data in a fixed network and the transmission of data over an air interface. The PDSN interfaces to a base system (BS) through a Packet Control Function (PCF), which may or may not be co-located with the BS.
As defined in the 3rd Generation Partnership Project 2; 3GPP2 Access Network Interfaces Interoperability Specification (hereinafter referred to as 3GPP2 A.S0001-A), which is herein incorporated by reference, there are three packet data service states: Active/Connected, Dormant, and Null/Inactive. (The 3GPP2 specification is the same in content as TIA/EIA/IS-2001-A June 2001.) When a MS station (MS) originates a packet data call to the current cdma2000 Radio Access Network (RAN), a traffic channel is allocated to establish a point-to-point protocol (PPP) connection and perform Mobile Internet protocol (IP) Registration procedures. Upon successful completion of these procedures, the MS's packet data service transitions from a Null to an Active/Connected state and the network and MS exchange packet data over a traffic channel. After a predefined period of inactivity, the MS's packet data service transitions from an Active to a Dormant state, however it may become Active again if the MS or network has data to send. Inter-PDSN Dormant mode handoffs also require the allocation of a traffic channel to support the setup of a new PPP connection and Re-Registration.
In the Active/Connected State, a physical traffic channel exists between a MS and a BS, and either unit may send data. In the Dormant State, no physical traffic channel exists between the MS and BS, but the PPP link between the MS and the PDSN is maintained. In the Null/Inactive State, there is no traffic channel between the MS and BS and there is no PPP link between the MS and the PDSN.
A1 through A11 interfaces are defined in Section 1.7.2 of 3GPP2 A.S0001-A. A1 and A8 connections are maintained during the Active/Connected state and released during transition to Dormant or Null/Inactive state. The A10 connection is maintained during the Active/Connected and the Dormant State. As part of the support for the Dormant State, the cdma2000 air interface (TIA/EIA-IS-2000) supports a Data Ready to Send (DRS) indicator that is used on Origination. When a MS sends an origination request with a packet data service option specified, the request includes the DRS bit. This indicator is set to 1 on initial call setup when the MS wishes to transition from Dormant to Active because it has data to send and is requesting the establishment of a traffic channel. Subsequently, the DRS bit is set to 0 to indicate that the MS has transitioned a packet zone boundary (see section 2.14.1 of 3GPP2 A.S0001-A) while Dormant, and is sending the origination request to update the network as to its current location.
Upon receipt of an origination request with the DRS bit set to 1, the BS initiates the call setup procedure as shown in Section 2.14.7.1 of 3GPP2 A.S0001-A, which normally results in the establishment of a traffic channel and in the A8 and A10 bearer connections being established. The procedures for the A8 and A10 bearer connections are defined in 3GPP2 A.S0001 -A, Sections 2.14 and 2.15, respectively. When the BS receives an origination with the DRS bit set to 0, the BS delays the establishment of a traffic channel until after the A8 and A10 bearer connection establishment procedures are complete. During the A8 bearer connection establishment procedure, the BS indicates to the PCF that a DRS=0 has been received through the use of the Data Ready Indicator element in the A9-Setup-A8 message (as defined in Section 2.14.4.1.1. of 3GPP2 A.S0001-A). If the PCF has data from the network to deliver to the MS, it indicates this by setting the cause element in the A9-Connect-A8 message (as defined in Section 2.14.4.1.2 of 3GPP2 A.S0001-A) to the Data Ready to Send value. The BS then establishes a traffic channel to the MS and completes a normal call setup procedure as specified in Section 2.14.7.10 of 3GPP2 A.S0001-A. If the PCF does not have data, it indicates that the A8 connection is not being established by sending the A9-Release-A8 Complete message (as defined in Section 2.14.5.4 of 3GPP2 A.S0001-A) to the BS. The BS then returns an Assignment Failure message to the MSC with the cause value set to Packet Call Going Dormant. Upon receipt of the Assignment Failure message, the MSC returns a Clear Command to the BS with the cause value set to Do Not Notify Mobile. The BS sends a Clear Complete message to the MSC upon receipt of the Clear Command message.